If you’re the CEO of a company, here’s another threat you need to worry about: hackers trying to recruit your employees for insider-related crimes.

Researchers at security firms RedOwl and IntSights have noticed growing activity from online black market dealers trying to recruit company employees for insider trading and cashing out stolen credit card numbers. 

These dealers are appearing on underground forums located on the dark web, which are accessible through Tor, a browser designed for anonymous web surfing, according to the researchers, who published their on Tuesday. 

Hackers in these underground forums have been looking for employees to collude in insider trading to make educated stock market bets. One site has been helping its members engage in this illicit activity, and garnered over 40 bitcoin ($39,755) in total transactions

that companies segregate valuable data from employees who have no reason to use it, or hire professionals to handle investigations that deal with suspected insider theft.